Rotary pumps and motors

ABSTRACT

A rotary fluid pump and motor is provided having a rotary impeller with axial stub shafts mounted in bearings at opposite ends of the impeller, a case enclosing the impeller and bearings, said case including a pair of end covers enclosing said bearings, an annular spacer member in each end cover at each bearing between said bearing and impeller having an axial annular flange extending toward but spaced from said impeller and impeller shaft between said impeller and bearing to form an annular pocket, a piston member in said annular pocket, an end plate against the end of said impeller between said impeller and said case and piston member, a plurality of radial slots in the end covers facing said end plate and a plurality of sealing members, one in each radial slot and bearing on said end plates forming pockets between the end covers and end plates and passage means from one side of the end plate to the other whereby fluid is delivered from the impeller to said pockets to provide balancing pressures on opposite sides of the plate and behind said piston member urging the same axially toward the impeller.

United States Patent [191 Boop et al.

[451 Aug. 20, 1974 1 1 ROTARY PUMPS AND MOTORS [75] Inventors: John L. Boop; Joseph P. Rudinec,

both of Youngstown, Ohio [73] Assignee: Commercial Shearing Inc.,

Youngstown, Ohio [22] Filed: Mar. 14, 1973 [21] Appl. No.: 341,148

[52] US. Cl. 418/131 [51] Int. Cl. F04c 15/00 [58] Field of Search 418/131, 132,133

[56] References Cited UNITED STATES PATENTS 2,312,891 3/1943 Ferris 418/133 2,714,856 8/1955 Kane..... 418/132 2,742,862 4/1956 Banker 418/132 2,809,592 10/1957 Miller et al. 418/132 2,974,605 3/1961 Murray 418/132 Primary Examiner-C. J. Husar in iLeonard,Smitha Attorney, Xgent, or Firm-Buell, Blenko & Ziesenheim emu [5 7] ABSTRACT A rotary fluid pump and motor is provided having a rotary impeller with axial stub shafts mounted in bearings at opposite ends of the impeller, a case enclosing the impeller and bearings, said case including a pair of end covers enclosing said bearings, an annular spacer member in each end cover at each bearing between said bearing and impeller having an axial annular flange extending toward but spaced from said impeller and impeller shaft between said impeller and'bearing to form an annular pocket, a piston member in said annular pocket, an end plate against the end of said impeller between said impeller and said case and piston member, a plurality of radial slots in the end covers facing said end plate and a plurality of sealing members, one in each radial slot and bearing'on said end plates forming pockets between the end covers and end plates and passage means from one side of the end plate to the other whereby fluid is delivered from the impeller to said pockets to provide balancing pressures on opposite sides of the plate and behind said piston member urging the same axially toward the impeller.

10 Claims, 4 Drawing Figures ROTARY PUMPS AND MOTORS This invention relates to rotary pumps and motors and particularly to pumps and motors with rotary impellers and to means for sealing the ends of the impellers.

Typical of pumps and motors with rotary impellers is the gear pump which has a pair of impellers in the form of meshing gears and a case extending around a portion of the periphery of each impeller to trap fluid on the low pressure side of the pump and carry it around to the high pressure side of the pump. The meshed teeth prevent any substantial return flow between the impellers as a result of the pressure differential between the low pressure and the high pressure sides of the pump. End plates at each end of the typical gear pump are provided to limit the return flow between the ends of the impellers and the case. A typical prior art arrangement is that shown in Kane US. Pat. No. 2,714,856. In that patent, end plates of figure-eight configuration are used at each end of the impeller gears between the gears and the case. The structure of the Kane patent was a very significant improvement in pump and motor structures for its time. Unfortunately structures such as that disclosed and claimed in the Kane patent are not satisfactory for modern high pressure pumps and motors having rotary impellers such as gears. The problem in such high pressure pumps is that the bearings must be so large to handle the increased loads that the plates of Kane have too little metal remaining between the high and low pressure sides of the pumps so that there is unbalanced wear and loss of efficiency in the pump.

We have developed a new rotary pump and motor structure and end plate structure which eliminates these problems. By the present structure we are able to balance the loads on the end plates without affecting their structural integrity and without loss of pump efficiency.

In the preferred embodiment of our invention we provide a rotary fluid machine comprising a rotary impeller having axial stub shafts, a bearing at each end of said impeller surrounding a portion of each said stub shaft, a case enclosing the impeller and bearings, said case including a pair of end covers enclosing said bearings, an annular spacer member in each end cover at each bearing between said bearing and impeller having an annular axial flange extending toward but spaced from the impeller and impeller shaft to form a pocket, an end plate against the end of said impeller between said impeller and said case and annular member, a piston member in said pocket between the spacer member and end plate, a plurality of radial slots in said end covers facing said end plates and a plurality of sealing members, one in each radial slot and bearing on said end plate forming pockets between the end covers and end plates and passage means from one side of the end plates to the other whereby fluid is delivered from the impeller side to the said pockets to provide a balancing pressure on each side of said plate and behind the piston member urging the same axially toward the impeller. Preferably the end covers are provided with three spaced radial slots at each bearing dividing each annular area into three pressure pockets.

In the foregoing general description we have set out certain objects, purposes and advantages of our invention. Other objects, purposes and advantages will be apparent from a consideration of the following description and the accompanying drawings in which:

FIG. 1 is a sectional view of a rotary gear pump and motor taken through the impeller axes;

FIG. 2 is a view of an end plate according to one embodiment of our invention showing its front face which engages the impeller ends;

FIG. 3 is an enlarged fragmentary section of an end cover spacer member, piston and end plate assembly as used in FIG. 1; and

FIG. 4 is an end view of an end cover as used in our invention, viewed from the left of FIG. 1.

Referring to the drawings we have illustrated a pump 10 which is also usable as a motor, having a pair of meshing gear impellers 11 and 12 between a pair of end plates 13 and 14, all within a central casing member 15 which encloses the outer peripheries of the impellers 11 and 12 and plates 13 and 14. Inlet and outlet ports, not shown, are provided as typical in gear motors and pumps in the casing member 15. The casing member 15 is enclosed between end bells or covers 16 and 17 held in place by bolts 18. Each end bell is provided with annular recesses 16a and b and 17a and b respectively which receive bearings 19 and 20 supporting hubs 21 and 22 respectively of the impellers 11 and 12. An annular ring member 23 having an axial flange 23a spaced from the supporting hubs to form a recess 24 is inserted in each of the recesses 16a, 16b, 17a and 17b between the bearings 19 and 20 and the end plates with the axial flange 23a extending toward the end plates. A power piston 25 is movable in the recess 24 and a seal means such as an elastomer ring 26 seals the joint between the power piston 25 and annular ring 23. Each end plate 13 and 14 is in the form of a Figure eight with a flat surface on both the front face adjacent the impeller ends and the rear face adjacent the end bells. The end plates are provided with radial slots or grooves 27-29 into which are placed pocket seals 30- 32 so as to form a plurality of pressure pockets between the end bells and the end plates. The pocket seals 30-32 are preferably elastomer seals which isolate the pressure areas 33-36 so as to form differential pressure pockets in each relieved area.

The periphery of each plate is cut away at each relieved area as indicated at 40, 41, 42 and 43. This cutaway portion provides passage for fluid at the pump gears to pass into and pressurize the differential pressure pockets. The unrelieved peripheral portions 50, 51, 52 and 53 engage the casing 15 in a snug sliding fit.

A slot or groove 37 is preferably provided in the end bells 16 and 17 to connect with a pair of grooves 38 and 39 in the spacer ring 23. These cooperating grooves provide a passage for pressure fluid into the recess 24 to act on the power piston 25. Preferably the end of the power piston 25 is relieved at the area where it contacts the end plates 13 and 14. The end plates 13 and 14 may be provided with a groove 13a-l4a to collect fluid and act as a pressure fluid lubricating ring.

Preferably the grooves 27-29 and their corresponding seals 30-32 extend from the root line of the gears to the inner periphery of the case so that the balancing pressure is brought down to the root line in each pocket.

The arrangement of this invention has many advantages over the prior art structures. It provides pressure areas and thus forces on both front and back of each end plate which can be closely controlled and balanced resulting in better performance at high pressure. It provides an effective root seal between the gear and end plate through a full 360. Leakage around the plate periphery is minimized because its thickness is minimal. The structure permits bi-directional rotation without sacrificing performance. Finally the structure is easily formed, particularly the end plates.

In the foregoing specification we have set out certain preferred embodiments of our invention. However, it will be understood that this invention may be otherwise embodied within the scope of the following claims.

We claim:

1. A rotary fluid pump and motor comprising a pair of cooperating rotary impellers, axial stub shafts mounted in bearings at opposite ends of said impeller, a case enclosing the impeller and bearings, said case including a pair of end covers enclosing said bearings, an annular spacer member in each end cover at each bear ing between said bearing and impeller having an axial annular flange extending toward but spaced from said impeller and its shaft between said impeller and bearing to form an annular pocket, a piston member in said annular pocket, an end plate against the end of said impeller between said impeller and said case and said piston member, a plurality of radial slots in the end plates facing said end covers and a plurality of sealing members, one in each radial slot and bearing on said end plates forming pockets between the case and end plates and passage means from one side of the end plate to the other whereby fluid is delivered from the impeller to said pockets to provide balancing fluid pressures on opposite sides of the plate and behind said piston member urging the same axially toward the impeller.

2. A rotary fluid pump and motor as claimed in claim 1 wherein a portion of the said case fits closely around a portion of the periphery of the impeller to trap fluid therebetween and with the periphery of the end plate alternately in contact with and substantially spaced from the case adjacent the said portion.

' 3. A rotary fluid pump and motor as claimed in claim 1 having a pair of cooperating rotary impellers and an end plate in the form of a figure eight.

4. A rotary fluid pump and motor as claimed in claim 1 wherein the spaced radial slots each carrying a sealing member define four pockets behind each end plate opposite each impeller.

5. A rotary fluid pump and motor as claimed in claim 4 wherein the sealing members are elastomer strips.

6. A rotary fluid pump and motor as claimed in claim 4 wherein passages are provided through said end plate between said radial slots providing communication between the impeller and said pockets.

7. A pressure plate arrangement for corresponding ends of a pair of cooperating impellers with axial shafts contained within a case and mounted in bearings in end covers on said case comprising an annular spacer member in said end covers at each bearing having an outer diameter equal to the corresponding bearing and between the bearing and impeller, a reduced diameter axial flange on said annular member extending toward the impeller and spaced from the axial shafts, an end plate against the end of said impellers between the annular members and impellers, a power piston in the recess in the annular member between said annular member and end plate, and a plurality of radial grooves in the end plates carrying sealing means forming pockets between the end covers and end plates and behind said piston member urging it axially toward the impeller.

8. A pressure plate arrangement as claimed in claim 7 wherein passage means are provided from one side of the plate to the other adjacent said pockets whereby fluid is delivered from said impeller to said pockets to provide balancing fluid pressures on opposite sides of the plate.

9. A pressure plate arrangement as claimed in claim 7 wherein the end plate is in the form of a figure eight.

tween the impeller and said pockets. 

1. A rotary fluid pump and motor comprising a pair of cooperating rotary impellers, axial stub shafts mounted in bearings at opposite ends of said impeller, a case enclosing the impeller and bearings, said case including a pair of end covers enclosing said bearings, an annular spacer member in each end cover at each bearing between said bearing and impeller having an axial annular flange extending toward but spaced from said impeller and its shaft between said impeller and bearing to form an annular pocket, a piston member in said annular pocket, an end plate against the end of said impeller between said impeller and said case and said piston member, a plurality of radial slots in the end plates facing said end covers and a plurality of sealing members, one in each radial slot and bearing on said end plates forming pockets between the case and end plates and passage means from one side of the end plate to the other whereby fluid is delivered from the impeller to said pockets to provide balancing fluid pressures on opposite sides of the plate and behind said piston member urging the same axially toward the impeller.
 2. A rotary fluid pump and motor as claimed in claim 1 wherein a portion of the said case fits closely around a portion of the periphery of the impeller to trap fluid therebetween and with the periphery of the end plate alternately in contact with and substantially spaced from the case adjacent the said portion.
 3. A rotary fluid pump and motor as claimed in claim 1 having a pair of cooperating rotary impellers and an end plate in the form of a figure eight.
 4. A rotary fluid pump and motor as claimed in claim 1 wherein the spaced radial slots each carrying a sealing member define four pockets behind each end plate opposite each impeller.
 5. A rotary fluid pump and motor as claimed in claim 4 wherein the sealing members are elastomer strips.
 6. A rotary fluid pump and motor as claimed in claim 4 wherein passages are provided through said end plate between said radial slots providing communication between the impeller and said pockets.
 7. A pressure plate arrangement for corresponding ends of a pair of cooperating impellers with axial shafts contained within a case and mounted in bearings in end covers on said case comprising an annular spacer member in said end covers at each bearing having an outer diameter equal to the corresponding bearing and between the bearing and impeller, a reduced diameter axial flange on said annular member extending toward the impeller and spaced from the axial shafts, an end plate against the end of said impellers between the annular members and impellers, a power piston in the recess in the annular member between said annular member and end plate, and a plurality of radial grooves in the end plates carryiNg sealing means forming pockets between the end covers and end plates and behind said piston member urging it axially toward the impeller.
 8. A pressure plate arrangement as claimed in claim 7 wherein passage means are provided from one side of the plate to the other adjacent said pockets whereby fluid is delivered from said impeller to said pockets to provide balancing fluid pressures on opposite sides of the plate.
 9. A pressure plate arrangement as claimed in claim 7 wherein the end plate is in the form of a figure eight.
 10. A pressure plate arrangement as claimed in claim 9 wherein passages are provided through said end plate between said radial slots providing communication between the impeller and said pockets. 